Reading Your Water Bill to Catch a Hidden Leak Early

Most slow leaks don't announce themselves with dramatic puddles. They show up as small increases in your water bill — increases small enough to dismiss as a billing error until they're not.

Pull the last twelve months

California water utilities show usage in CCF (hundred cubic feet) or gallons. One CCF equals 748 gallons. Most households use 5 to 12 CCF per month depending on size and landscape. If your January is normally 6 CCF and this January it's 9 CCF, you're losing 2,244 extra gallons somewhere.

Eliminate the obvious

Has your household grown? New landscape? New tenant or guest? Hot summer raising irrigation? Account for these before assuming a leak. If everything's normal but usage isn't, move to the meter test.

Run the meter test

Turn off every faucet and water-using appliance. Locate your water meter (usually street-side curb). The flow indicator is a small triangle or asterisk that moves when water flows. If it's moving with everything off, water is escaping somewhere downstream of the meter. That's your leak.

Common slow-leak sources

Toilet flapper leaks (silent, expensive, very common). Hose bibs in the side yard with worn washers. Irrigation drip lines buried under mulch. Slab leaks in older copper. Water heater pan drains that drip into a hidden floor drain. Each has a different fix, but all show up on your bill before they show up on your floor.

When to escalate

If meter test confirms a leak but you can't find the source, you need a plumber with leak-detection equipment. California water districts often have rebate programs for leak repair if you're losing significant water — check your local utility website.